LGTM
The part about "is 0.01" is not precisely correct. The numbers below are
the real ones. It doesn't matter because in a Go program 0.01 used in a
float64 context really means
0.01000000000000000020816681711721685132943093776702880859375, but it
will avoid confusion later if we are precise here.
Also, although I didn't note it below, I think it might help to use
panic(fmt.Sprintf("F=%.1000g, want %.1000g", F, F32))
because the default printer for float64s is not very precise and perhaps
not even very accurate.
https://codereview.appspot.com/6855053/diff/10001/test/fixedbugs/bug470.go
File test/fixedbugs/bug470.go (right):
https://codereview.appspot.com/6855053/diff/10001/test/fixedbugs/bug470.go#newcode11
test/fixedbugs/bug470.go:11: var F = float64(float32(0.01))
var F = float64(float32(0.01))
const (
F32 = 0.00999999977648258209228515625
F64 = 0.01000000000000000020816681711721685132943093776702880859375
)
https://codereview.appspot.com/6855053/diff/10001/test/fixedbugs/bug470.go#newcode14
test/fixedbugs/bug470.go:14: // 0.01 rounded to float32 then to float64
is 0.009999999776482582.
is F32.
next line
is F64.
https://codereview.appspot.com/6855053/diff/10001/test/fixedbugs/bug470.go#newcode16
test/fixedbugs/bug470.go:16: if F == 0.01 {
if F != F32 {
panic(F)
}
https://codereview.appspot.com/6855053/
